<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title></title>
</head>

<body>
    <script>
        var pretime = getNowFormatDate();
        console.log(pretime); 
        var minute = 1000 * 60;
        var hour = minute * 60;
        var day = hour * 24;
        var halfamonth = day * 15;
        var month = day * 30;

        //这是第一次打开页面时调用
        getDate(pretime);

        //然后再每隔一分钟更新一次时间
        setInterval(function () {
            getDate(pretime);
        }, 60000);

        function getDate(dateTimeStamp) {

            if (dateTimeStamp == undefined) {

                return false;
            } else {
                dateTimeStamp = dateTimeStamp.replace(/\-/g, "/");

                var sTime = new Date(dateTimeStamp).getTime();//把时间pretime的值转为时间戳

                var now = new Date().getTime();//获取当前时间的时间戳

                var diffValue = now - sTime;

                if (diffValue < 0) {
                    console.log("结束日期不能小于开始日期！");
                }

                var monthC = diffValue / month;
                var weekC = diffValue / (7 * day);
                var dayC = diffValue / day;
                var hourC = diffValue / hour;
                var minC = diffValue / minute;

                if (monthC >= 1) {
                    console.log(parseInt(monthC) + "个月前");
                }
                else if (weekC >= 1) {
                    console.log(parseInt(weekC) + "周前")
                }
                else if (dayC >= 1) {
                    console.log(parseInt(dayC) + "天前")
                }
                else if (hourC >= 1) {
                    console.log(parseInt(hourC) + "个小时前")
                }
                else if (minC >= 1) {
                    console.log(parseInt(minC) + "分钟前")
                } else {
                    console.log("刚刚")
                }
            }

        }
        // 获取当前网页打开时间
        function getNowFormatDate() {
            var date = new Date();
            var seperator1 = "-";
            var seperator2 = ":";
            var month = date.getMonth() + 1;
            var strDate = date.getDate();
            var strHours = date.getHours();
            var strMinutes = date.getMinutes();
            var strSeconds = date.getSeconds();

            if (month >= 1 && month <= 9) {
                month = "0" + month;
            }
            if (strDate >= 0 && strDate <= 9) {
                strDate = "0" + strDate;
            }
            if (strHours >= 0 && strHours <= 9) {
                strHours = "0" + strHours;
            }
            if (strMinutes >= 0 && strMinutes <= 9) {
                strMinutes = "0" + strMinutes;
            }
            if (strSeconds >= 0 && strSeconds <= 9) {
                strSeconds = "0" + strSeconds;
            }

            var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate
                + " " + strHours + seperator2 + strMinutes
                + seperator2 + strSeconds;
            return currentdate;
        }
    </script>
</body>

</html>